PhotoVoltaic (PV) solar panels are becoming an important source of electrical power. Large, megawatt arrays with panels numbering in the tens of thousands are increasingly common. BIPV (Building Integrated PhotoVoltaic) power generation in which the panels are integral to a building itself (e.g. roofing tiles) is also becoming popular. A typical PV panel array is organized into many small groups of panels (typically tens of panels in a group) connected to a local power bus. These local buses connect to a main power bus.
PV panels are necessarily exposed to the outside weather and have a typical service lifetime requirement of tens of years. Over this lifetime an individual panel's connection to the power bus may be subject to corrosion from moisture ingress, mechanical stress from wind or snow loads, thermal cycling and other environmental factors, resulting in a deterioration of the connection quality and high connection resistance. The local power bus is also subject to similar stress and problems. Increased connection resistance can lead to undesirable lost power, overheating or fire.
Manual monitoring of the quality of the array's power connections is undesirable since it would be time consuming and require the creation of special test points for access. BIPV panels pose additional problems since they may not be at ground level and their cabling runs can be hidden between the panel and the building and therefore difficult to access and inspect.